Field of the Disclosure
The present disclosure relates generally to three-way catalyst (TWC) systems, and more particularly, to synergized-PGM TWC catalysts with ultra-low PGM loadings employed in underfloor configurations for reduction of emissions from engine exhaust systems.
Background Information
Three-way catalyst (TWC) systems continue to be implemented as the primary emission control strategy for internal combustion engines within vehicles. However, a period of rapidly evolving production road maps for engine/combustion improvements that are tied to energy efficiency has recently begun by the automotive industry. Associated catalytic improvements will need to go beyond the fine tuning of platinum group metals (PGM) usage and rare earth (RE) metals used as oxygen storage materials (OSM) and will present important challenges to catalyst developers.
The trend toward more stringent tailpipe regulations, noted from the global tightening of the light and heavy duty emission standards, have led to important improvements in the development of modern catalysts including: improved fuel economy and reduction of greenhouse gas emissions requirements that establish lower exhaust temperatures; and material supply issues related to the supply and demand of PGM materials as a result of their availability and price volatility. As changes in the formulation of catalysts continue to increase the cost of TWC systems, the need for catalysts of significant catalytic performance has directed efforts toward the development of catalytic materials capable of providing the required synergies to achieve greater catalytic performance. Additionally, compliance with ever stricter environmental regulations, and the need for lower manufacturing costs require new types of TWC systems. Therefore, there is a continuing need to provide TWC systems, employing reduced amounts of PGM catalyst materials and that are free of RE metals, which exhibit catalytic properties substantially similar to or exceeding the catalytic properties exhibited by conventional TWC systems employing standard amounts of PGM catalyst materials and RE metals.